Cortical Activation Related to Motor and Sensory Tasks in Congenital Mirror Movement using Functional MRI

ABSTRACT

BACKGROUND: Mirror movements are symmetric, identical, contralateral involuntary movements that accompany vol-untary movements on one side of the body. The aim of this study is to examine the patterns of brain activation during motor and sensory tasks using a functional magnetic resonance imaging (fMRI) and to compare them between normal subjects and a patient with congenital mirror movements. METHODS: A 19 year-old patient with congenital mirror movements and seven normal volunteers (mean age 29 years old), performed finger-tapping and tactile stimulation tasks with the right, left, and both hands, while gradient echo EPI (echo planar imaging) images were acquired in a 1.5T scanner. RESULTS: During the motor and sensory tasks, the patient showed a bilateral activation of the primary motor and sensory cortices, whereas normal subjects showed only unilateral activations. Activations related to the motor task was observed in the primary sensory cortex, the supplementary motor area, and the cerebellum as well as the primary motor cortex in the case of the patient, while only the primary motor cortex was significantly activated in normal subjects. CONCLUSIONS: These findings suggest that the abnormality underlying congenital mirror movements involves not only the primary motor cortices and interhemispheric connections between them, but also the more extended motor-sensory circuitry including the primary sensory cortex, supplementary motor area, and cerebellum.